1. Technical Field
The present invention relates to transport methods and recording apparatuses.
2. Related Art
Inkjet printers are known as recording apparatuses in which a medium (such as paper or cloth for example) is transported in a transport direction and recording is carried out on the medium by a head. In such a recording apparatus, when a transport error occurs while transporting the medium, the head cannot record on a correct position on the medium. In particular, with inkjet printers, when ink droplets do not land in the correct position on the medium, there is a risk that white streaks or black streaks will occur in the printed image and image quality deteriorates.
Accordingly, methods are proposed for correcting transport amounts of the medium. For example, in JP-A-5-96796 it is proposed that a test pattern is printed and the test pattern is read, and correction values are calculated based on a reading result such that when an image is to be recorded, the transport amounts are corrected based on the calculated values.
When using a transport roller to transport the medium, DC component transport error and AC component transport error occur as transport errors. Here, DC component transport error refers to a predetermined amount of transport error that occurs when the transport roller has performed one rotation. And AC component transport error refers to transport error corresponding to a location on a circumferential surface of the transport roller that is used when transporting.
If the DC component transport error varies according to a relative position between the medium and the transport roller, it is necessary to prepare a plurality of correction values corresponding to the relative positions. And the greater the numbers of correction values for correcting the DC component transport error are, the finer the corrections can be made. However, in obtaining correction values for correcting DC component transport error, when a test pattern is printed by printing the pattern each time the transport roller performs one rotation, the number of correction values obtained from the test pattern is small.